Embodiments of the present invention relate to computer software, and more particularly relate to techniques for facilitating the sharing of metadata by a plurality of software applications.
In recent years, an increasing number of software applications are being built using a metadata-driven approach. These applications (referred to herein as metadata-driven applications) are structured such that aspects of their content, behavior, and/or appearance are specified via metadata rather than program code. For example, Service-Oriented Architecture (SOA) applications typically rely on data and services that are defined using Extensible Markup Language (XML) based metadata (e.g., Web Services Description Language (WSDL) documents, XML Schema Definition (XSD) documents, etc.).
Large-scale software applications or application suites (such as the Oracle E-Business Suite developed by Oracle Corporation) may include a number of metadata-driven applications or application components that make use of the same metadata. For instance, the applications may use one or more common metadata documents that describe a standard user interface layout, standard data types, or the like. In these situations, the common metadata should be made available to all of the applications in some manner.
According to one approach, such common metadata can be made available to applications by simply duplicating the metadata in each application. Unfortunately, this approach is problematic for several reasons. For example, since each application must include its own, separate copy of the common metadata, problems may occur where applications are accidentally deployed with mismatched metadata versions, resulting in incorrect runtime behavior. Further, maintaining duplicate versions of metadata is inefficient and cumbersome. For example, the size of each application will be larger than necessary because of the duplicated metadata, and any modifications to the metadata will require updates to each duplicated copy.
According to another approach, the common metadata can be stored in a centralized location, and the various applications can retrieve the single, shared copy using proprietary means (i.e., means that do not leverage any standard access mechanisms such as Uniform Resource Locators (URLs)). While this method overcomes some of the difficulties related to duplicating common metadata, this method still has several shortcomings. For instance, each application will have to implement proprietary code for accessing the shared copy of the metadata, rendering the application incompatible with a large number of existing application framework components and standards (e.g., development tools, XML processors, WSDL, etc.) that are adapted to reference metadata documents as URLs.